VB.Net Tutorial/Collections/Array Class

Array.Copy: Copy elements by position

Public Class Tester
    Public Shared Sub Main
        Dim arrayA() As String = {"One", "Two", "Three", "Four", "Five", "Six"}
        Console.WriteLine(Join(arrayA, ","))
        Dim arrayB() As String = {"A", "B", "C", "D", "E", "E", "F", "G", "H"}
        Console.WriteLine(Join(arrayB, ","))
        " ----- Make a reference copy.
        Dim arrayC() As String = arrayA
        Console.WriteLine(Join(arrayC, ","))
        " ----- Copy elements by position.
        Array.Copy(arrayB, 0, arrayA, 1, 3)
        Console.WriteLine(Join(arrayA, ","))
    End Sub
End Class

One,Two,Three,Four,Five,Six
A,B,C,D,E,E,F,G,H
One,Two,Three,Four,Five,Six
One,A,B,C,Five,Six

Array.CreateInstance(GetType(Integer), 11)

public class Test
  
   public Shared Sub Main
        Dim values As Array = _
            Array.CreateInstance(GetType(Integer), 11)
        For i As Integer = 0 To 10
            values.SetValue(i, i)
        Next i
   End Sub
   
End class

Array.CreateInstance(GetType(String), 10)

Option Strict On
Imports System.Collections.Generic
Public Module TypeNameFunction
   Public Sub Main()
      Console.WriteLine(TypeName(2 + 1.34))            " displays Double
      
      Dim arr1 As Array = Array.CreateInstance(GetType(String), 10)
      Console.WriteLine(TypeName(arr1))
      Dim stringArray(10) As String
      Console.Writeline(TypeName(stringArray))
      Dim sl As New SortedList(Of String, String)
      Console.WriteLine(TypeName(sl))
   End Sub
End Module

Double
String()
String()
SortedList(Of String,String)

Array.GetLength, Array.GetUpperBound

public class Test
   public Shared Sub Main
        Dim aryStatistics(14, 4) As Integer
        Console.WriteLine("RANK: " & aryStatistics.Rank) "Dimensions in array.
        Console.WriteLine("TOTAL ELEMENTS: " & aryStatistics.Length) "Total elements in array.
        Console.WriteLine("ELEMENTS IN FIRST: " & aryStatistics.GetLength(0)) "Elements in first dimension.
        Console.WriteLine("ELEMENTS IN SECOND: " & aryStatistics.GetLength(1)) "Elements in second dimension.
        Console.WriteLine("LAST INDEX IN FIRST: " & aryStatistics.GetUpperBound(0)) "Last index in the first dimension.
        Console.WriteLine("LAST INDEX IN SECOND: " & aryStatistics.GetUpperBound(1)) "Last index in the second dimension.
   End Sub
End class

RANK: 2
TOTAL ELEMENTS: 75
ELEMENTS IN FIRST: 15
ELEMENTS IN SECOND: 5
LAST INDEX IN FIRST: 14
LAST INDEX IN SECOND: 4

Array.IndexOf

public class Test
  
   public Shared Sub Main
        Dim values(10) As Integer
        For i As Integer = 0 To 10
            values(i) = i
        Next i

        Console.WriteLine(Array.IndexOf(values, 6).ToString)
   End Sub
   
End class

6

Array.LastIndexOf

public class Test
  
   public Shared Sub Main
        Dim values(10) As Integer
        For i As Integer = 0 To 10
            values(i) = i
        Next i
        Console.WriteLine(Array.LastIndexOf(values, 3).ToString)
   End Sub
   
End class

3

Array SetValue and GetValue

Imports System.Collections.Generic
public class Test
  
   public Shared Sub Main
        Dim squares As Array = Array.CreateInstance(GetType(Integer), 11)
        For i As Integer = 0 To 10
            squares.SetValue(i * i, i)
        Next i
        For i As Integer = 0 To 10
            Console.WriteLine(squares.GetValue(i).ToString)
        Next i
   End Sub
   
End class

0
1
4
9
16
25
36
49
64
81
100

Copy array elements from one array to another

Module Tester
    Sub Main()
        Dim Values() As Integer = {100, 200, 300, 400, 500}
        Dim MyValues(5) As Integer
        Dim Prices() As Double = {25.5, 4.95, 33.4}
        Dim I As Integer
        For I = 0 To 4
            Console.Write(Values(I) & " ")
        Next
        Console.WriteLine()
        " Copy one array to another
        Values.CopyTo(MyValues, 0)
        For I = 0 To 4
            Console.Write(MyValues(I) & " ")
        Next
    End Sub
End Module

100 200 300 400 500
100 200 300 400 500

Get Enumerator from array

Imports System.Collections
Module Module1
    
    Sub Main()
        Dim StringArray() As String = {"This", "is", "a", "test"}
        Dim E As IEnumerator = StringArray.GetEnumerator()
    
        While (E.MoveNext())
          Console.WriteLine(E.Current())
        End While
    
        Dim AnArray(5) As Array
        AnArray(0) = StringArray
        Console.WriteLine(CType(AnArray(0), String())(0))
    
    
    End Sub
End Module

This
is
a
test
This

One dimensional Array with Array.CreateInstance

public class Test
  
   public Shared Sub Main
        Dim start_time As DateTime
        Dim stop_time As DateTime
        Dim elapsed_time As TimeSpan
        Dim num_items As Integer = 10000

        " One-dimensional Array.
        Dim array3 As Array = _
            Array.CreateInstance(GetType(Integer), num_items)
        start_time = Now
        For i As Integer = 0 To num_items - 1
            array3.SetValue(i, i)
        Next i
        stop_time = Now
        elapsed_time = stop_time.Subtract(start_time)
        Console.WriteLine(elapsed_time.TotalSeconds())
        
        Erase array3
   End Sub
   
End class

0

Reverse array elements

Module Tester
    Sub Main()
        Dim Values() As Integer = {100, 200, 300, 400, 500}
        Dim MyValues(5) As Integer
        Dim Prices() As Double = {25.5, 4.95, 33.4}
        Dim I As Integer
        For I = 0 To 4
            Console.Write(Values(I) & " ")
        Next
        Console.WriteLine()
        Values.Reverse(Values)
        For I = 0 To 4
            Console.Write(Values(I) & " ")
        Next
        Console.WriteLine()
    End Sub
End Module

100 200 300 400 500
500 400 300 200 100

Two-dimensional Array with Array.CreateInstance

public class Test
  
   public Shared Sub Main
        Dim start_time As DateTime
        Dim stop_time As DateTime
        Dim elapsed_time As TimeSpan
        Dim num_items As Integer = 10000
        " Two-dimensional Array.
        Dim array4 As Array = _
            Array.CreateInstance(GetType(Integer), 1, num_items)
        start_time = Now
        For i As Integer = 0 To num_items - 1
            array4.SetValue(i, 0, i)
        Next i
        stop_time = Now
        elapsed_time = stop_time.Subtract(start_time)
        Console.WriteLine(elapsed_time.TotalSeconds())
        Erase array4
   End Sub
   
End class

0

Use Array.Sort() to sort object array

Imports System
Module MyModule
  Sub Main()
    Dim salaries(4) As Salary
    salaries(0) = New Salary(9)
    salaries(1) = New Salary(4)
    salaries(2) = New Salary(8)
    salaries(3) = salaries(2)
    salaries(4) = New Salary(6)
    Console.WriteLine("Unsorted array:")
    Dim salary As Salary
    For Each salary In salaries
      Console.WriteLine("{0}", salary)
    Next
    Array.Sort(salaries)
    Console.WriteLine(vbCrLf & "Sorted array:")
    For Each salary In salaries
      Console.WriteLine("{0}", salary)
    Next
  End Sub
End Module
Structure Salary
  Implements IComparable
  Private value As Integer
  Public Sub New(ByVal amount As Double)
    Me.value = CInt(amount * 100)
  End Sub
  Public Function CompareTo(ByVal other As Object) As Integer Implements IComparable.rupareTo
    Dim m2 As Salary = CType(other, Salary)
    If Me.value < m2.value Then
      Return -1
    ElseIf Me.value = m2.value Then
      Return 0
    Else
      Return +1
    End If
  End Function
  Public Overrides Function ToString() As String
    Return Me.value
  End Function
End Structure

Unsorted array:
900
400
800
800
600
Sorted array:
400
600
800
800
900